


Unleashed

by kittenofdoomage



Category: Marvel Cinematic Universe
Genre: Alpha/Beta/Omega Dynamics, Alpha/Omega, F/M, Knotting, Mating Cycles/In Heat, Rough Sex, Rutting, Sex, Smut
Language: English
Status: Completed
Published: 2018-12-11
Updated: 2018-12-11
Packaged: 2019-09-16 11:41:08
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,238
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16953333
Author URL: https://archiveofourown.org/users/kittenofdoomage/pseuds/kittenofdoomage
Summary: Steve wasn’t an Alpha originally; the serum changed him. Now, seventy years later, he’s going through his first rut, threatening the start of your relationship.





	Unleashed

The phone had rung unanswered three times now and you were getting concerned. Steve didn’t normally ignore your calls unless he was in some sort of trouble and it had been a while since he’d found himself in any. And it was Tuesday.

It all added up to a big pile of worry that distracted you from what you were supposed to be doing.

Sam landed a punch to your face that hurt and you went down like a sack of shit, clutching your face and glaring at him. “Keep your eyes on your game, Y/L/N,” he barked, frowning as he offered you his hand. “You’re all over the damn place today.”

“Worried about Steve,” you murmured, working the ache out of your jaw. Sam instantly stopped, his expression filled with concern.

“What about Steve?”

“He’s not answering my calls.”

“And?” Sam shrugged. “It’s his day off. He’s probably sleeping.”

You gave him a dry look. “We’re talking about the same person, right? Steve doesn’t take  _days off_.” Huffing, you turned away. “I’m gonna drive over and check on him. He’s been funny with me all week.” Sam rushed to catch up and you glanced at him in bewilderment. “What are you doing?”

“Comin’ with,” he insisted. “Steve’s my best friend. You think I’m gonna let his girl waltz off into possible danger without back-up?”

Snorting, you held the door open, gesturing for him to go first. “I doubt he’s in that much trouble. He was fine when I saw him on Saturday.” Sam hummed skeptically but didn’t say anything else as you drove through the city to Steve’s apartment.

Traffic into Brooklyn was awful and you growled in frustration at the backup onto the bridge. Sam sighed, shaking his head. “Wings would have been quicker.”

“Can’t be a superhero for everything, Sam,” you muttered, tapping your hands on the wheel. You were antsy and on edge, unreasonably worried about Steve. Something in the pit of your belly was clawing to get out and you had no clue what it was.

Things were relatively new between you and the superhuman Alpha. You’d been dating for months, sticking to Steve’s old-fashioned preferences, which was sweet. He’d never had an Omega and hadn’t really adjusted to how easy-going people were these days.

While you’d slept together on multiple occasions, Steve hadn’t knotted you. He hadn’t put his mark on your neck, something that you were still unsure on. It felt like he was it, the one you were supposed to be with but the possibility of either one of you dying in the line of duty made you uncomfortable with the grief that would follow.

It was unusual for anyone to survive it.

“Look,” Sam said suddenly, “we’re only three blocks away. Why don’t you go ahead on foot and I’ll bring the car round.”

You glanced over at him, raising an eyebrow. “You’re sure.”

“Yeah,” Sam dismissed, unclipping his belt. Without any further encouragement, you climbed out of the car, running through the crowded sidewalks as fast as you could. Steve’s apartment building was right up ahead and you crashed through the door, apologizing to the doorman whose name you could never remember.

The elevator was out again so you bolted up the stairs, panting despite your enhanced endurance as you reached Steve’s apartment. You knocked, getting no answer, but as you stopped to catch your breath, inhaling deep lungfuls of oxygen, you knew the problem.

Your knees buckled as Steve’s thick rut-scent saturated your senses. Retrieving your phone from your pocket with shaking fingers, you dialled Sam’s number, waiting patiently for him to answer.

“ _Y’ello?_ ”

“Sam,” you swallowed, leaning against the door for support. “Turn around, go home, Steve’s fine.”

“ _What? Y/N, what’s goin’ on?_ ”

“Nothing you want to know about,” you muttered, closing your eyes. The scent was growing stronger - Steve knew you were here. “Seriously, Sam, go home, I’ll check in with you later.” Hanging up without waiting for an answer, you laid your hand on the door handle, taking a deep breath, unwittingly making your thighs clench at the Alpha scent thick in the air.

The lock clicked, unlocking from the other side and you twisted the door handle, pushing open the door slowly. Steve stood on the other side, shirtless and barefoot. His rut had taken hold, causing him to sweat profusely and breathe as if he’d run a marathon.

“Steve,” you murmured, quickly moving inside the apartment and shutting the door, locking it behind you. He grimaced, his fists clenching at his sides. “Why didn’t you answer my calls?”

A violent shudder ran through his body and Steve ground his teeth together. “You shouldn’t have come here,” he panted. “It’s…” He swallowed, holding his own stomach. “It’s never been this bad before.”

His skin was hot to the touch; and he stiffened when your palm landed on his chest and you met his eyes, noticing the extreme dilation of his pupils. “You need to be in bed.”

“I know what I need,” Steve grunted, pulling away from you. “I shouldn’t have let you in.”

“Why?”

He was so strung out, he couldn’t focus and you stepped back, knowing it was like spitting on an inferno to try and put it out. Steve grabbed his head. “Steve, I need you to talk to me.”

“Because I want you,” he growled, refusing to look at you. “And I don’t know if I can keep control.”

God, his scent was intoxicating. You shuddered, throwing caution to the wind as you stepped closer to him. “What if I can take it? Is that why you won’t -”

“You’re not like me, Y/N,” Steve whispered, backing away from you now and you raised an eyebrow. “I mean with healing and… I’m a lot stronger than you.” His back was against the wall now but you didn’t stop, too swept away with arousal from his scent. “Y/N,” he murmured when you were an inch from touching him.

“Alpha?” you replied, running your hands up over his shoulders, feeling the same fire in his skin take hold in yours.

Steve’s strength gave out and he pulled you close, dragging your mouth to his. The kiss was more teeth than tongue but you didn’t care, desperate to feel him. “Can’t hold back,” the Alpha snarled, his hands gripping your ass. “Gonna knot you,” he kissed along your jaw, biting lightly at the spot below your ear, “gonna mark you.”

The sound that left you was amplified by his hands pulling at your shirt. He was pulling you toward the bedroom now, barely able to separate from your body as he tried to perform multiple tasks at once.

“Steve,” you gasped when he gave up and hoisted your legs around his waist, thick arms supporting your weight easily. Throwing your arms around his neck, you carried on kissing him, letting him carry you toward the bed. His name left your lips again but Steve didn’t reply, tearing your shirt over your head and ripping a seam in the process.

Your skin was slick now, his rut forcing your body into heat; the air was saturated with Alpha pheromones, fogging your mind with nothing but the need to mate.

Steve’s sweats disappeared and you immediately grabbed for his cock, relishing the sound he made when you curled your fingers around his shaft. Slowly, you started to pump it, teasing him even more, despite the threat of how strong this Alpha was.

His biceps flexed as he seized your wrist, forcing you to release him so he could turn his attention to removing the rest of your clothing. One shoe ended up in the hallway - the other clattered against the dresser and perched itself on the edge.

Your panties were nothing against the super-soldier’s grip, tearing easily, left as nothing but a scrap on the floor. Steve grabbed your hips and flipped you, making you shriek in surprise, the sound melting away to a groan when his mouth connected with your throbbing slit.

Lowering your head to the bed, you pushed your ass up further in the air; Steve responded by growling and thrusting his tongue into your soaked hole. He ate you out like he’d never done before - you didn’t think he liked it but the way he was stroking you with his tongue now, barely coming up for air, you assumed he was a fan.

You knew you were, now at least.

Steve didn’t relent until you came, practically gushing over his chin and he pulled his head up, wiping his mouth with the back of his hand. You attempted to turn, to reach for him, but he batted your hands away with a growl. “Later.”

His hand pressed your shoulders back down into the covers - the other fisted his cock, guiding it to your slick and ready hole.

“Wanna feel you,” he groaned, the tip of his shaft kissing your pussy for a teasing second that lasted an eternity. When he finally pushed his hips forward, sinking into your welcoming heat with little resistance, you both gasped. Steve didn’t stop until he was buried to the hilt, his balls resting against your clit as he let you feel him, thick and throbbing inside you.

Euphoria suffused your body when he moved. You could feel the steady shudder of his arms holding his weight off of you, still keeping a leash on his control. It was sweet but not what you needed. Vanilla was all well and good for any old day of the week but Steve was in rut and you were rapidly falling into an impromptu heat.

“Steve,” you whispered, “let go. You won’t hurt me.”

He shook his head, keeping his pace slow and you squirmed, attempting to pull away. A low growl made you freeze and Steve’s hand snaked underneath your belly. “Stay,” he panted, “still.”

“Then give me what I need,” you replied, just as breathless. “I know you need it too. You won’t hurt me,” you paused, glancing over your shoulder at him, surprised how black his eyes were, “at least, not in a way I won’t like.”

His fingers curled against your stomach and he pushed up, placing his hands on your ass. “You want my knot, Omega?” he asked, rubbing his thumb over the sensitive spot at the tail of your spine. “Want me to fill you up?”

“Yes,” you begged, nodding your head frantically.

Neither of you mentioned the fact that his cock was bare inside you. You didn’t acknowledge the little warning in the back of your mind, reduced to primal need for your Alpha’s knot.

Steve didn’t move immediately. He squeezed your asscheeks in his hands, eyes glued to the spot where your bodies were connected. When he pulled out slowly, he could see the slick white evidence of your arousal on his shaft and he groaned, easing back in.

“So pretty,” he murmured, unusually bold for the mild-mannered Captain America you were accustomed to. The low words made your insides clench and Steve chuckled. “You like me praising you, huh?” You nodded and he laughed again. “God, I never thought I’d have you like this.”

“Like what?”

His finger trailed over your asshole. “Open for me,” he said quietly, “taking every inch like you were built for it,” you whined and he continued, “like you were made to be mine.”

A throb seemed to roll through your womb and Steve groaned loudly, picking up a little speed. You couldn’t think for the repeated slam of his cockhead into your cervix that sent electric shocks directly to your pleasure center.

He was moving faster and faster with each thrust, pushing you higher into oblivion that ended with a scream from your kiss-swollen lips. Steve grunted as his knot started to thicken, catching on your tight entrance.

“Gonna knot you,” he snarled, dragging his teeth across your shoulder blade. “Mark you.” One hand splayed across your belly again; the other pulled you upright against his chest. You rolled your head to the side, submissively exposing your throat and the sound the Alpha made wasn’t even slightly human.

Blinding pleasure seemed to short-circuit your body as you came and Steve’s knot locked inside you, his teeth sinking into your skin at the same time as he pumped ropes of cum into your warm pussy. He growled like an animal, holding you tightly enough that you felt like you couldn’t breathe.

Steve calmed before you did, lowering you both onto your sides so you could try and catch your breath. Peppering kisses along your shoulder and arm, you relaxed into his hold, sighing contentedly.

“I didn’t think you’d want it,” he muttered and you frowned, wishing you could turn to face him. “I’m not… I’m not that Alpha, I promise. I just -”

“Steve,” you cut him off, covering his hand with yours where it rested across your hip, “you don’t have to explain anything. I’m an Omega; I know what happens with an Alpha’s rut. And with you not being an Alpha originally…”

“I know. Heightened aggression where it comes to my mate.”

“Not unusual,” you whispered, smiling as you dragged his hand up to kiss his knuckles. “And I’m assuming you’ve got world class stamina to go along with that.”

Steve chuckled, nuzzling into your hair. “That was just round one. I hope you don’t have anywhere to be.”


End file.
